Method and fingerprint sensing system for forming a fingerprint representation

Abstract

The present invention generally relates to a method for forming a fingerprint using a fingerprint sensing system, and specifically to the possibility of allowing the formation of a fingerprint when only separated portions of the fingerprint is available. The invention also relates to the corresponding fingerprint sensing system and to a computer program product.

What is claimed is: 
     
       1. A method of forming a fingerprint representation of a fingerprint pattern of a finger captured using a fingerprint sensor, the method comprising the steps of:
 acquiring a first partial image of a corresponding first portion of a fingerprint pattern using the fingerprint sensor; 
 extracting a first fingerprint feature from the first partial image; 
 acquiring a second partial image of a corresponding second portion of the fingerprint pattern using the fingerprint sensor, the second partial image being non-overlapping with the first partial image; 
 extracting a second fingerprint feature from the second partial image; 
 determining a first parameter for each of the first and the second fingerprint feature, the first parameter being at least one of a representation of a relative spatial fingerprint position for the respective fingerprint feature and a representation of a relation of the fingerprint feature to the finger, wherein determining the first parameter for each of the first and the second fingerprint feature comprises correlating at least one of the first and the second fingerprint features with a fingerprint feature of a previously acquired fingerprint representation; and 
 forming the fingerprint representation by correlating the first parameter for the first fingerprint feature with the first parameter for the second fingerprint feature. 
 
     
     
       2. The method according to  claim 1 , wherein the second partial image is acquired at a subsequent instance in time in comparison to the acquisition of the first partial image, and the step of determining the first parameter for each of the first and the second fingerprint feature comprises at least one of:
 determining a duration between the acquisition of the first and the second partial image, and 
 determining a speed of the finger being swiped over the fingerprint sensor. 
 
     
     
       3. The method according to  claim 2 , further comprises the step of determining a spatial relation between the first and the second fingerprint feature based on the first parameter. 
     
     
       4. The method according to  claim 1 , wherein the first parameter for the first fingerprint feature and the first parameter for the second fingerprint feature are related to the same finger of a user. 
     
     
       5. The method according to  claim 1 , wherein the step of forming the fingerprint representation comprises appending the previously acquired fingerprint representation with at the least one of the first and the second fingerprint feature. 
     
     
       6. The method according to  claim 1 , wherein the step of correlating at least one of the first and the second fingerprint features with a fingerprint features of a previously acquired fingerprint representation is part of a process of enrolling the finger. 
     
     
       7. The method according to  claim 1 , wherein the extraction of the first fingerprint feature from the first partial image is performed independent on the extraction of the second fingerprint feature from the second partial image. 
     
     
       8. The method according to  claim 1 , wherein the fingerprint sensor is a line sensor. 
     
     
       9. The method according to  claim 2 , further comprising the step of determining the position of the finger at an instance in time of acquiring the first and the second partial image. 
     
     
       10. The method according to  claim 9 , wherein the fingerprint sensor is arranged adjacently to a touch display, and the step of determining the position of the finger is based on data received from the touch display. 
     
     
       11. The method according to  claim 1 , further comprising the steps of
 acquiring a fingerprint template representative of an enrolled fingerprint of a finger, and 
 authenticating the formed fingerprint representation. 
 
     
     
       12. A fingerprint sensing system, comprising:
 a fingerprint sensor; 
 a memory; and 
 processing circuitry for forming a fingerprint representation of a fingerprint pattern of a finger captured using the fingerprint sensor, the processing circuitry connected to the fingerprint sensor and further configured for:
 acquiring a first partial image of a corresponding first portion of a fingerprint pattern using the fingerprint sensor; 
 extracting a first fingerprint feature from the first partial image; 
 acquiring a second partial image of a corresponding second portion of the fingerprint pattern using the fingerprint sensor, the second partial image being non-overlapping with the first partial image; 
 extracting a second fingerprint feature from the second partial image; 
 determining a first parameter for each of the first and the second fingerprint feature, the first parameter being at least one of a representation of a relative spatial fingerprint position for the respective fingerprint feature and a representation of a relation of the fingerprint feature to the finger, wherein determining the first parameter for each of the first and the second fingerprint feature comprises correlating at least one of the first and the second fingerprint features with a fingerprint feature of a previously acquired fingerprint representation; and 
 forming the fingerprint representation by correlating the first parameter for the first fingerprint feature with the first parameter for the second fingerprint feature. 
 
 
     
     
       13. The fingerprint sensing system according to  claim 12 , wherein said fingerprint sensor is a capacitive fingerprint sensor. 
     
     
       14. The fingerprint sensing system according to  claim 12 , wherein the fingerprint sensor is a line sensor. 
     
     
       15. The fingerprint sensing system according to  claim 12 , wherein the processing circuitry is further configured for:
 acquiring a fingerprint template representative of an enrolled fingerprint of a finger, and 
 authenticating the formed fingerprint representation. 
 
     
     
       16. An electronic device, comprising:
 the fingerprint sensing system according to  claim 12 ; and 
 at least one processor for:
 providing an authentication request for said finger to the fingerprint sensing system; 
 receiving an authentication signal from the fingerprint sensing system; and 
 performing at least one action only if said authentication signal indicates authentication success. 
 
 
     
     
       17. The electronic device according to  claim 16 , wherein the electronic device is a mobile phone. 
     
     
       18. A computer program product comprising a non-transitory computer readable medium having stored thereon computer program means for controlling a portable electronic device, the portable electronic device comprising a fingerprint sensing system including a fingerprint sensor and processing circuitry, the fingerprint sensing system adapted for forming a fingerprint representation of a fingerprint pattern of a finger captured when swiped over the fingerprint sensor, wherein the computer program product comprises:
 code for acquiring a first partial image of a corresponding first portion of a fingerprint pattern using the fingerprint sensor; 
 code for extracting a first fingerprint feature from the first partial image; 
 code for acquiring a second partial image of a corresponding second portion of the fingerprint pattern using the fingerprint sensor, the second partial image being non-overlapping with the first partial image; 
 code for extracting a second fingerprint feature from the second partial image; 
 code for determining a first parameter for each of the first and the second fingerprint feature, the first parameter being at least one of a representation of a relative spatial fingerprint position for the respective fingerprint feature and a representation of a relation of the fingerprint feature to the finger, wherein determining the first parameter for each of the first and the second fingerprint feature comprises correlating at least one of the first and the second fingerprint features with a fingerprint feature of a previously acquired fingerprint representation; and 
 code for forming the fingerprint representation by correlating the first parameter for the first fingerprint feature with the first parameter for the second fingerprint feature.